32 Experiments tLpon Gimpowder. 



I was convinced that I could not be mistaken in the 

 fact, for it had been my constant practice to take hold 

 of the piece to wipe it out as soon as an experiment 

 was finished, and I never before had found any incon- 

 venience from the heat in holding it. But in order to 

 put the matter beyond all doubt, after letting the barrel 

 cool down to the proper temperature, I repeated the 

 experiment twice, with the same charge of powder and 

 a bullet; and in both these trials (experiments No. i8 

 and No. 19), the heat of the piece" was evidently much 

 less than what it was in the experiment above mentioned 

 (No. 17). 



I now regretted exceedingly the loss of a small pocket 

 thermometer, which I had provided on purpose to 

 measure the heat of the barrel, but it was accidentally 

 broken by a fall the day before I began my experi- 

 ments ; and, being ,so far from London, I had it not 

 in my power to procure another ; I was, therefore, 

 obliged to content myself with determining the heat 

 of the barrel as well as I could by the touch. 



Being much struck v/ith this accidental discovery of 

 the great degree of heat that pieces acquire when they 

 are fired with powder without any bullet, and being 

 desirous of finding out whether it is a circumstance that 

 obtains universally, I was very attentive to the heat of 

 the barrel after each of the succeeding experiments ; 

 and I constantly found the heat sensibly greater when 

 the piece was fired with powder only than when the 

 same charge was made to impel one or more bullets. 



Though the result of these experiments was totally 

 unexpected, and even contrary to what I should have 

 foretold, if I had been asked an opinion upon the sub- 

 ject previous to making them, yet, after mature con- 



